


The Descendant Materialization

by darling_pet



Category: Supergirl (TV 2015), The Flash (TV 2014)
Genre: Alternate Universe, Alternate Universe - Time Travel, Crime Fighting, Crossover, Dating, F/M, Future children - Freeform, Reader is Supergirl, Reader-Insert, Relationship(s), Time Travel, descendant
Language: English
Status: Completed
Published: 2017-05-24
Updated: 2017-05-24
Packaged: 2018-11-04 06:54:22
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,140
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10985703
Author URL: https://archiveofourown.org/users/darling_pet/pseuds/darling_pet
Summary: In a universe where you, the Reader, are National City’s very own Supergirl (and dating the ever-dashing Flash), a surprise arises when one of your descendants accidentally travels back in time to your present day…





	The Descendant Materialization

**Author's Note:**

> This fic came from an anon tumblr request :)

__

 

_Pow! Boom! Shazzam!_

Ok, you really had to stop making sound effects in your head when tripping up and disarming criminals. But what you find especially amusing was how confident these bank robbers had seemed in the beginning. Even when you dropped down in front of them with your suit’s family emblem staring back at them, they simply laughed. As if being Supergirl didn’t mean anything to them.

Well, maybe if the citizens of National City didn’t give you such a girly superhero name they wouldn’t find you so funny.

_Bam! Pew! Who’s laughing now, boys?_

The man with the duffle bag full of cash grabs a civilian woman and points his gun at her.

“Careful, girl scout! Or the broad gets it!” You put your hands up as if to say, _whoa now._

“Okay, okay. Relax, be cool,” you try to calm him down. “Just hand over the nice lady.”

“And you’ll let me run?”

“Sure.”

“Really?”

“Why not?”

“It’s just, that’s not really your thing.”

“Are we gonna talk about it all day or do you want to get a head start? Because you’ll need it.” Before the robber can think too much about it, he shoves the lady into you and makes a dash down the street. You know he won’t get very far.

_Three… Two… One._ A blur of red leaving yellow lighting trails darts by you, causing your hair to blow wildly. A smile curls on your lips. Taking a big leap, you land in front of the robber and his red-masked subduer.

“Well, _Flash_ , fancy seeing you here,” you say in a voice coated with hints of an inside joke.

“Supergirl. What a pleasant surprise,” he replies. You look at the defeated crook.

“Told ya you’d need that head start.”

 

 

 

After the righteous takedown, you return home to your apartment in Midtown National City (in regular citizen clothes once again). Waiting in the elevator, you push your glasses up the bridge of your nose into place. When the elevator reaches your floor, you look down the hallway to see a male body leaning against your door checking his phone. You walk up to him and wrap your arms around him.

“Hi, Bare.” You kiss his cheek. He slides his phone into his back pocket and wraps you in his arms.

“Hey,” he grins. “You were great earlier.”

“Me? You’re the one who whizzed by and snatched the guy up!”

“But you giving him false hope of getting away? And saving that woman with your wit? Priceless!” You both laugh as you open the door to your loft apartment. Even though Barry has his own place on the other side of town, he still practically lives with you. Throwing yourself down on the couch, Barry follows suite and snuggles up next to you.

“I feel like I could eat the entirety of supplies from all the Big Belly Burgers in the city,” you say dramatically. Barry kisses the back of your head.

“I’ll go pick us up some grub,” he offers. “The usual?” You nod. “Be back in a flash!” Before you scoff at the bad pun, he has already returned with take-out bags.

“ _Barry!”_

“What? That was funny.”

You seriously have the best boyfriend.

As Barry unpacks the food, his and your phone start going off. You answer yours as you drool over the fast food spread out in front of you.

“(Y/N), you gotta get down here.” It’s Winn. “There’s something you have to see.” His tone is strange. Not quite urgent, but sort of weirded out.

“Winn, what’s going on? Is there trouble?” You shoot a look to Barry, on the phone with who you’re assuming is Cisco. It sounds like they’re having a similar conversation.

“Not _trouble_ …”

“We’re on our way.”

You fly at top speed to the DEO. _What could it be now? Another alien attack? More high-priority_ _superhumans_ _on the loose?_ Whatever it was, you were ready.

You arrive at the building the exact second Barry does. _Damn_. You thought you had him beat this time. The DEO crew all stands in a huddle at the other end of the room. You stride over to them.

“Hey!” you call out to them. “What’s going on?” All heads turn at the sound of your voice.

“You’ll never guess. Like _ever,_ ” Winn teases.

“What was the call about?” Barry asks, very confused by all the secret keeping.

“Dude, I know it’s way too early, but congratulations,” Cisco says patting him on the back. Barry and you share a _WTF?_ glance.

“What-?” The gang’s huddle opens up and reveals a beautiful long legged girl, possibly in her late teens. Long hair, bright eyes. And when she lays eyes on you and Barry, the girl’s face lights up like a Christmas tree. She walks up to both of you and wraps her arms around you in a big group hug. This pretty teen kind of looks familiar, but you don’t know why. _Who is this? Should I know her?_

“You both look so _young_!” she squeals with joy.

“Sorry, um, who might you be, exactly?” you ask her.

“I’m Ellie. _Ellie Allen_. Your daughter!”

Okay, maybe you _weren’t_ ready. If your expression is anything like Barry’s, you’re wide-eyed and mouth left agape. You look around at your friends for help, an explanation. Anything.

“Dibs on godfather!” yells Cisco.

Winn argues, “Hey, so not fair!”

 

 

“What’s _Back to the Future_?”

“Oh my God!” Cisco shouts. “Barry, (Y/N), you’ve already officially failed at becoming parents.”

“I think what Cisco is trying to say, Ellie, is that it’s not good for someone to know too much about their future,” Barry tries to explain. “And, no offence, you might be that ‘too much.‘”

“I’m sorry, Dad,” she apologizes. _Whoa._ That was a shock to the system. “When I ended up here, I didn’t know what to do. But then when I learned what year it was, I remembered you guys telling me you used to work for the DEO together when you were younger. So I came here.”

J'onn steps in with the question, “And how exactly did you come to be here in this time?”

“Training exercise gone wrong, apparently. See, my teammate slash rival has teleportation powers and I guess when she blasted them at me she overshot by _many years_.”

“What kind of training exercise are we talking about?” you ask. Ellie looks at you with so much awe and love. It completely blows your mind how much she looks like both you and Barry at once. Ellie giggles.

“Oh! I guess you wouldn’t know, yet! Watch this!” In a split second your daughter has left and returned, having placed a single flower in everyone’s hair (except for J'onn, who had one in his shirt pocket). You are even more stunned.

“You’re a Speedster,” you remark.

“That’s right!” Ellie says brightly. “Just like my old man. But don’t worry Mom, I have some of your awesome powers, too.” Her eyes grow red and the beams of light melt a potted plant in half, creating a mess.

“Oops.”

“Clean up on aisle twelve!” Winn shouts enthusiastically.

“Yo, that’s dope,” Cisco admires.

“Anyway, as much as I’d like to live in this retro time, I need to get back. I just don’t know how to go about it…”

“I might know a guy,” Barry says. At that, you and him escort Ellie to the lower levels of the DEO where the company’s resident scientists, Harrison Wells and Caitlin Snow, run experiments, tests, and come up with new tech. The two heads in the room look up from their respective works.

“Barry, (Y/N),” Caitlin greets. “Who have you brought with you?”

“This is Ellie,” you introduce. “She’s our- our-”

“She’s our daughter,” Barry finishes. The room is silent.

“How is that possible?” Ellie goes on to fill Caitlin in on what happened. Harrison slowly approaches your daughter and extends a hand for her to shake.

“Harrison Wells. Pleasure to meet you, Ellie.” He examines her face, then Barry’s, then yours. “Truly remarkable,” he marvels at the time travelling anomaly that is your teenage daughter.

“We need to get her back to her time,” you say.

“Do you think you can help me?” Ellie asks. Harrison makes a thinking gesture with his index finger and thumb over his mouth.

“Absolutely,” he says. “But first, Miss Allen, if I have the permission of your parents, I’d like to run a few tests…”

 

 

For the next few days, the members of the DEO are bustling around with the new task of trying to send Ellie home. Especially Cisco, Caitlin, Wells, and Winn (or as you sometimes call them, C2W2). In the meantime, while the crew works on creating a sort of time portal, Ellie stays with you and Barry at your apartment. It is the most bizarre thing in the world to live with your daughter who isn’t technically even born yet. At first, it was awkward, no doubt. But after awhile, things started to smooth out. She really was an extraordinary girl. You and Barry were clearly going to be very lucky parents.

Towards the middle of the week, Ellie appears to be getting antsy, so you decide to take her along with you to CatCo. A sort of secret take-your-daughter-to-work-day, but of course, you introduce her as your cousin. You show her your latest article and she’s thrilled with your piece. She even mentions she has an interest in the field and was totally acing her writing class in school back in her time.

_Atta girl!_

After hearing about her CatCo experience with you, Barry wants in on the parent-daughter action and takes her to the National City Police Department to work a case the following day. You get to hear from Ellie later on about how cool it was surveying a crime scene.

“She’s got a great eye,” Barry praises.

“What a talent,” you agree. Ellie beams back at you both. But then her eyes flick to the TV and becomes distracted. _What is she looking at…_

It’s breaking news. A high-speed car chase on the freeway heading out of the city. Inside the vehicle? Thirty million dollars worth of jewelry. You and Barry stand up at the same time, tense.

“Ready to go, Bare?”

“Always.”

“I’m coming, too!” Ellie insists.

“No.” The word was said in unison.

“You’ve got to be kidding,” she protests.

“No, we’re not,” Barry says sternly. “You stay here.”

“Okay, well, I guess I’ll just…” _Zip._ She’s gone.

“Your daughter just disobeyed us!” you cry.

“Oh, so because she acted out, she’s _my daughter,_ ” Barry half jokes. “Let’s go.” Barry bolts away while you tear off your clothes to reveal your super-suit and fly out your window. Below you, Barry’s a red blur on the highway heading north-west. Keeping your top speed, you’re positive you can reach the speeding jewel thief before he reaches the city limits. Except… up ahead the police have the thief surrounded. He’s now in handcuffs! _How-?_

Ellie, that’s how.

You touch down on the ground just as she calls out to the thief, “Nice try, scumbag!” Barry’s shows up behind you and his hand finds your shoulder.

“She definitely picked up snarky comments and name-calling criminals from you.”

 

 

After about two weeks, you receive word that the DEO Labs team has finally finished the portal project. Something of this magnitude, you had expected it to take much longer than it did. Then again, the project was conducted by world genius Harrison Wells, so anything was possible with him at the helm. You knew Ellie had to get back home, but a part of you wished she wasn’t leaving already.

The portal hums the moment Cisco switches it on. Everyone groups together to say goodbye to your daughter, hugs and all. You hear Cisco reminding her to watch Spielberg’s time travelling adventure when she gets back. After Barry gets a little misty eyed saying his farewells, it’s your turn, and you hug Ellie tight in your arms. You aren’t sure what to say.

“Take care of yourself, my girl,” is what comes out.

“I will, Momma.” She lets go and addresses you and Barry one final time. “Dad, twelve year old me will beg for a puppy. All I ask is to just think about it. You have over twenty years to mull it over. And Mom- If, let’s just say, hypothetically in the future I happen to accidentally destroy your favourite vase. Go easy on me, please?” Ellie advances toward the portal, but not before giving the room a little wave.

“See you… later?” Her laugh that follows it almost makes you choke up.

You dreaded saying goodbye to Ellie. But you can’t wait to say hello to her again someday.

**Author's Note:**

> Anonymous Request: "If you watch Supergirl and The Flash, would you mind doing an imagine where the reader is Supergirl and she and The Flash are a crime-fighting duo and are dating and know about each other’s secret identies, S.T.A.R. Labs doesn’t exist and Cisco, Caitlin, and Harrison Wells work with the DEO, and their daughter is a speedster from the future and she accidentally ran back in time while doing a training excerise with her team and the gang has to help her get back to her time?"


End file.
